Classical mechanics Definition and 1000 Threads
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Why is the tension in a falling chain not equal to ρgy?
Firstly, There is something I want to clarify. When the system starts moving, parts of the chain that still lies on the table, which have mass ## \frac {(L- y_0)M} {L}##, will be pulled by the force that the hanging chain's weight exert,right? If yes, then : As far as I know, the formula ##F=...- Rikudo
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- Chain Classical mechanics Falling Morin
- Replies: 4
- Forum: Introductory Physics Homework Help
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I Phase space integral in noninteracting dipole system
Hi all, Consider a system of ##N## noninteracting, identical electric point dipoles (dipole moment ##\vec{\mu}##) subjected to an external field ##\vec{E}=E\hat{z}##. The Lagrangian for this system is...- raisins
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- Classical mechanics Electric dipole Integral Lagragian Partition function Phase Phase space Space Statistical mechanics
- Replies: 2
- Forum: Classical Physics
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Understanding Acceleration and Center of Mass in Shock Absorption
I don't attempt solving a problem until I fully understand it, conceptually. After the hit (when maximum velocity is reached) the person starts losing momentum, having a constant upwards acceleration. The forces acting on the person are gravity and the normal to the ground. $$N - mg = ma$$...- ThEmptyTree
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- Center of mass Classical mechanics compressive strength Impulse momentum Strength Stress and strain
- Replies: 5
- Forum: Introductory Physics Homework Help
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Books that teach classical mechanics through a discourse method
Books that teaches classical mechanics through a discourse method ie asking interesting questions and answering them maybe a similar one to Understanding Basic Chemistry Through Problem Solving: The Learner's Approach Book by Jeanne Tan and Kim Seng Chan. Not exactly asking numerical questions...- Viishnuuu
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- Books Classical Classical mechanics Mechanics Method
- Replies: 10
- Forum: Science and Math Textbooks
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Stopping a Bullet: Calculate umin and xf
(a) ##u_{min}=\big(1+\frac{m_2}{m_1}\big)\sqrt{2\mu_k g d}## (b) ##x_f=\sqrt{\frac{2h}{g}\Big(\big(\frac{m_1}{m_1+m_2}u\big)^2-2\mu_k g d\Big)}## Can someone check please?- ThEmptyTree
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- Bullet Classical mechanics Collision Conservation of momentum Friction Projectile motion
- Replies: 3
- Forum: Introductory Physics Homework Help
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Two Pulleys, Two Strings and Two Blocks
Someone pls solve this. I've done it but I'm not sure if it's correct. Thanks!- ThEmptyTree
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- Blocks Classical mechanics Constrained motion Pulley system Pulleys Rope Strings Tension Two blocks
- Replies: 4
- Forum: Introductory Physics Homework Help
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I Trouble simplifying the Lagrangian
Hello, I have posted a similar thread on this question before, but I'd like to get some help to simplify the answers I've got so far in order to match the solutions provided. If anyone could help me, I would really appreciate it. Since (c) is quite similar to (b), I'll leave here what I've done... -
I Trouble understanding coordinates for the Lagrangian
Hello, I'm having some trouble understanding this solution provided in Landau's book on mechanics. I'd like to understand how they arrived at the infinitesimal displacement for the particles m1. I appreciate any kind of help regarding this problem, thank you! -
I Understanding the Coordinates in the Lagrangian for a Pendulum
So I've been studying classical mechanics and have come across a small doubt with the solution provided to the problem in question from Landau's book. My question is: why are the coordinates for the particle given as they are in the solution? I imagine it has something to do with the harmonic... -
B How is the acceleration proportional to the removed force?
Image above is the question. Below image depicts solution. if F1 is removed then the acceleration of that mass must be sum of accelerations of remaining forces. Right?? But answer says that acceleration of that mass is equal to acceleration of F1. I don't understand it. Can someone explain it?? -
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Tension in rope wrapped around a rod
- ThEmptyTree
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- Classical mechanics Rod Rope Tension
- Replies: 3
- Forum: Introductory Physics Homework Help
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Work & Energy (Question on Classical Mechanics/Slope based Problems)
I used the Change in Kinetic Energy and equated that with the Work Done. The "Work Done" part comprises of two different functions- one is work done by Gravitational Force while the other is the work done by frictional force (or the brakes). /Delta KE (magnitude wise)= 0.5*1350* (20^2)=270,000...- warhammer
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- Classical Classical mechanics Energy Introductory physics Work
- Replies: 7
- Forum: Introductory Physics Homework Help
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How to find the constant in this indefinite integration?
$$x(t)=\int \dot{x}(t)\mathrm dt=vt+c$$ That's what I did. But, book says $$x(t)=\int \dot{x}(t)\mathrm dt=x_0+v_0 t+ \frac{F_0}{2m}t^2$$ Seems like, $$x_0 + \dfrac{a_0}{2}t^2$$ is constant. How to find constant is equal to what?- Istiak
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- Classical mechanics Constant Indefinite Integration
- Replies: 20
- Forum: Calculus and Beyond Homework Help
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Calculating Velocity when Stuntman Jumps from 1.25m Height
> >A stuntman jumped from $1.25 \ \text{m}$ height and, landed at distance $10 \ \text{m}$. Find velocity when he jumped. (Take $\text{g}=10 \ ms^{-2}$) I had solved it following way. $$h=\frac{1}{2}gt^2$$ $$=>1.25=5\cdot t^2$$ $$=>t=\frac{1}{2}$$ And, $$s=vt$$ $$v=\frac{s}{t}$$ $$=\frac{10 \...- Istiak
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- Classical mechanics Height Motion Velocity
- Replies: 30
- Forum: Introductory Physics Homework Help
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Why used $\cos\theta$ for $\text{y}$ axis or, gravitational force?
><br/> >Mass M1 is held on a plane with inclination angle θ, and mass M2 hangs over the side. The two masses are connected by a massless string...- Istiak
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- Axis Classical mechanics Force Gravitational Gravitational force
- Replies: 2
- Forum: Introductory Physics Homework Help
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How much of the wooden timber was submerged in water?
>Mass of a timber is $20 \ g$. And, density of that timber is $0.27 \ g/cc$. That timber was bind to a metallic materials and, it was released to $0.970 \ g/cc$ water. How much the wood was submerged in water? I was trying to solve the problem following way. $$F=Ah\rho g$$ $$=V\rho g$$ $$=V \...- Istiak
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- Classical mechanics Submerged Water
- Replies: 2
- Forum: Introductory Physics Homework Help
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I Total angular momentum of a translating and rotating pancake
I have read Classical Mechanics book by David Morin, and there are some parts that I do not understand from its derivation. Note : ## V## and ##v## is respectively the velocity of CM and a particle of the body relative to the fixed origin , while ##v'## is velocity of the particle relative to... -
Tricky conceptual Projectile motion question
So far all I have determined is the equations of motion for the two and that is as follows. It is trivial that y(t)=v1sin(Q)t -gt^2/2 and that x(t)=v2cos(Q)t. Now the angle that is anticlockwise from the negative horizontal of the robber is 90 - Q using basic trigonometry, using this we can...- Rubberduck2005
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- Classical mechanics Conceptual Motion Projectile Projectile motion Vectors
- Replies: 14
- Forum: Introductory Physics Homework Help
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I Verse from "A Brief History of Time"
1.One can now see why all bodies fall at same rate: A body of twice the weight will have twice the force of gravity pulling it down, but it will also have twice the mass. According to Newton’s second law these two effects will exactly cancel each other, so the acceleration will be same in all...- rudransh verma
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- Classical mechanics History Time
- Replies: 22
- Forum: Mechanics
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I Help with Goldstein Classical Mechanics Exercise 1.7
I'm trying to solve the Goldstein classical mechanics exercises 1.7. The problem is to prove: $$\frac{\partial \dot T}{\partial \dot q} - 2\frac{\partial T}{\partial q} = Q$$ Below is my progress, and I got stuck at one of the step. Now since we have langrange equation: $$\frac{d}{dt}... -
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I Time derivative of the angular momentum as a cross product
I am trying to find the equations of motion of the angular momentum ##\boldsymbol L## for a system consisting of a particle of mass ##m## and magnetic moment ##\boldsymbol{\mu} \equiv \gamma \boldsymbol{L}## in a magnetic field ##\boldsymbol B##. The Hamiltonian of the system is therefore... -
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What is the tension of the rope?
I have attached two different attempts to solve this problem. They both look correct to me but they give two different answers! Which one is correct, which one is wrong and why?- Ebi
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- Classical mechanics Newtonian mechanics Rope Tension
- Replies: 54
- Forum: Introductory Physics Homework Help
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Symmetries in Lagrangian Mechanics
In Classical Mechanics by Kibble and Berkshire, in chapter 12.4 which focuses on symmetries and conservation laws (starting on page 291 here), the authors introduce the concept of a generator function G, where the transformation generated by G is given by (equation 12.29 on page 292 in the text)... -
Building a motorcycle, need classical mechanics help
Hi! I am an engineering graduate that took my bachelor's degree in Mechanical Engineering much too long ago, but I have forgotten a lot of the classical mechanics/mechanics of materials theory that I had learned many years ago. I am building a motorcycle right now, and I want to calculate the...- Feroyn
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- Building Classical Classical mechanics Mechanics Motorcycle
- Replies: 4
- Forum: Mechanical Engineering
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Analyzing an Angular Impulse Problem
What we know: The ball is dropped at the tip A with some speed ##v_0## and rebounds with speed ##v##. This collision produces an angular impulse, changing the angular momentum of the bar with the flywheels. Solution inspired by an answer provided by @TSny in the similar question. Angular...- PiEpsilon
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- Angular Angular momentum Classical mechanics Impulse Moment of inertia
- Replies: 12
- Forum: Introductory Physics Homework Help
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Question on Moment of Inertia Tensor of a Rotating Rigid Body
Hi. So I was asked the following question whose picture is attached below along with my attempt at the solution. Now my doubt is, since the question refers to the whole system comprising of these thin rigid body 'mini systems', should the Principle moments of Inertia about the respective axes...- warhammer
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- Body Classical mechanics Inertia Inertia tensor Intro physics Moment Moment of inertia Rigid body Rotating Rotational dynamics Tensor
- Replies: 4
- Forum: Introductory Physics Homework Help
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Finding the period of an orbit ##r=a(1+\cos\theta)##
I've already found the potential and force that produce the given orbit. my results were: ##V=-\frac{al^2}{mr^3}## ##\vec{F}=-\frac{-3al^2}{mr^4}\hat{r}## Now, I've been trying to find the period using the equation ##t=\sqrt{\frac{m}{2}}\int_{r_0}^{r}\frac{dr'}{\sqrt{E-V_{eff}}}## Using...- Davidllerenav
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- Central forces Clasccal mechanics Classical mechanics Orbit Orbits Period
- Replies: 26
- Forum: Advanced Physics Homework Help
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Speed of a hanging rope sliding on a nail (using energy conservation)
I solved this problem easily using Newton's second law, but I had problems trying to use mechanical energy conservation to solve it. How I solved using Newton's second law: ##\text{(part of the rope that is on the left)}\, m_1=x\rho g,\, \text{(part of the rope that is on the right)}\...- TheGreatDeadOne
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- Classical Classical mechanics Conservation Conservation of energy Energy Energy conservation Rope Sliding Speed
- Replies: 6
- Forum: Introductory Physics Homework Help
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How Can the Stability of a Kapitza Pendulum Be Demonstrated?
I understand that when $$A_0 \gg g$$, the g term in the equation of motion can be dropped. The equation of motion then becomes $$\frac{d^2\theta}{dt^2}=-\frac{a_d(t)}{L}\sin\theta$$ But how can I show that the pendulum is stable for such case? I am totally clueless.- HansBu
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- classical mechanics harmonic pendulum stability
- Replies: 5
- Forum: Advanced Physics Homework Help
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Motion involving Translation & Rotation |Kleppner and Kolenkow
My doubt is with Method 2 of the given example in KK. I'm unable to understand why the torque around A (where we have chosen a coordinate system at A) becomes zero due to the R x F in z direction with a minus sign {Photo Attached} I have tried to reason out that one way to formulate that term... -
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Classical Reading Goldstein's Classical Mechanics as an Undergraduate
We were prescribed Goldstein, Taylor and Marion/Thornton for our first course in analytical mechanics, and I'm about to finish up the course but I feel like I have not gotten a good physical, intuitive grasps of the concepts, so I've been trying to read the texts a bit more. Taylor and...- IAmLoco
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- Classical Classical mechanics Mechanics Reading Undergraduate
- Replies: 33
- Forum: Science and Math Textbooks
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A Something about configuration manifolds in classical mechanics
I think it could be interesting. Consider a mechanical system A circle of mass M can rotate about the vertical axis. The angle of rotation is coordinated by the angle ##\psi##. A bead of mass m>0 can slide along this circle. The position of the bead relative the circle is given by the angle...- wrobel
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- Classical Classical mechanics Configuration Manifolds Mechanics
- Replies: 2
- Forum: Differential Geometry
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Does any classical mechanics textbook solve Kepler's Problem?
I have several* classical physics and mechanics texts, and none solve the Kepler problem (as far as I can tell), succinctly, solving the Kepler equation, M = E - e*sin(E), for E given M and e, or more generally determining the equations of motion for an orbiting object. In fact none even...- Will Flannery
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- Classical Classical mechanics Mechanics Textbook
- Replies: 22
- Forum: STEM Educators and Teaching
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Particle constrained on a curve
I tried 1. using the Lagrangian method: From ##y=-kx^2## I got ##\dot y = -2kx \dot x## and ##\ddot y = -2k \dot x^2 - 2 kx \dot x##. (Can I use ##\dot y = g## here due to gravity?) This gives for kinetic energy: $$T = \frac{1}{2} mv^2 = \frac{1}{2} m (\dot x^2 + \dot y^2) = \frac{1}{2} m (\dot...- randy
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- Classical mechanics Constrained motion Curve Lagrangian Particle
- Replies: 9
- Forum: Introductory Physics Homework Help
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I Why is action considered a scalar in physics?
Why is the action a scalar? Please explain.- Adams2020
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- Classic physics Classical mechanics Scalar
- Replies: 8
- Forum: Classical Physics
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Equation of motion of a marble moving on a generic vertical guide
Hello to everyone :smile: I'd like to study this problem. You have a 2D guide, described by an equation y = y (x) in a reference interval x ∈ I = [a, b], placed in a cartesian vertical plane Oxy. The guide is frictionless and the only force that is acting is the gravity force. On this track, a... -
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Classical Recommend books about classical mechanics please
Hi! i need some textbooks recommendations to learn by my self about classical mechanics in a undegraduate level. I don´¨¨t know what kind of math is required, i have knowledge about calculus by my high school classes and i learned more with the book "Calculus" by Gilbert Strang. I wait for your...- Santiago24
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- Books Classical Classical mechanics Mechanics
- Replies: 11
- Forum: Science and Math Textbooks
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What Other Types of Motion Exist Beyond Translation, Rotation, and Oscillation?
In high school I learned about three kinds of motion in classical mechanics - translation, rotation, and oscillation. Are there any other kinds of motion in the physical world? -
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Does Teaching by Numbers Limit Understanding of Elasticity in Rubber Bands?
If you take a rubber band and fix it in a stretched position for an extended period of time, would it eventually lose its elasticity? If yes, then how can you calculate how long it would take until its elasticity decreases by a certain amount, say, fifty percent? If no, why not? How does the... -
I The center of mass & relativistic collisions
In special relativity (especially relativistic collisions), is the center of mass frame as useful as Newtonian mechanics?- Adams2020
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- Center Center of mass Classical mechanics Collisions Mass Mechanic Modern physics Relaitivity Relativistic Special relativity
- Replies: 7
- Forum: Special and General Relativity
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I Energy in the Hamiltonian formalism from phase space evolution
The hamiltonian ´for a free falling body is $$H = \dfrac{p^2}{2m} + mgy$$ and since we are using cartesian coordinates that do not depend on time and the potential only depends on the position, we know that ##H=E##. For this hamiltonian, using the Hamilton's equations and initial conditions...- Jaime_mc2
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- Classical mechanics Energy Evolution Hamiltonian Hamiltonian formalism Phase Phase space Space
- Replies: 1
- Forum: Classical Physics
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Classical Prerequisites for Arnold's Methods of Classical Mechanics
I've finished with Gregory's classical mechanics and was looking for something a bit more challenging. I thought Arnold's methods of classical mechanics look pretty interesting, but it's definitely more mathematically complex than anything I would have done before, especially the bits about...- etotheipi
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- Classical Classical mechanics Mechanics Prerequisites
- Replies: 11
- Forum: Science and Math Textbooks
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MHB Is the Given Answer for the Classical Mechanics Problem on Earth Correct?
- WMDhamnekar
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- Classical Classical mechanics Mechanics
- Replies: 3
- Forum: General Math
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Deriving Statistical Behavior of Particles via Classical Mechanics
Hello, using computation simulation, can the statistical behavior of many particles be derived through deterministic classical mechanics? -
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Classical mechanics -- Equations for simulating the motion of a body
Hello forum, i want to make a samulation of a body. The body will be moved horisontal on y,x axis. I want on my simulation the body to change direction many times(for example i want to go for 10sec right and then left end right...). My question is does i need more than one differential equation... -
Estimate the initial velocity of the cars after the collision
What came to my mind for this question is: Consider one of the cars. The velocity and mass of this car are V and M respectively. And the velocity and mass of the piece attached to the car are m, v respectively. Before the collision, the velocity of this piece relative to this car is zero. So its...- peace
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- Cars Classic physics Classical mechanics Collision Estimate Initial Initial velocity Mechancis Velocity
- Replies: 29
- Forum: Introductory Physics Homework Help
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Calculating Tension on Strings: Results & Confusion
Attempt: By drawing the Free Body diagrams and calculating the different tensions, I got the following results ##T_1=\frac{(M_1+M_2)}{2}g## ##T_2=\frac{\sqrt 3(M_1+M_2)}{2}g## ##T_3=M_2g## But, I am not sure what the answer is as although ##T_2>T_1## but ##T_3## does not depend on ##M_1##...- Saptarshi Sarkar
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- Classical mechanics Newton 3rd law Strings Tension
- Replies: 4
- Forum: Introductory Physics Homework Help
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Can We Cancel the Derivative of dt in These Equations?
problem in this book : classical mechanics goldstein Why can we cancel the derivative of dt from these equations? e.g. ##\frac{d(x)}{dt} + \frac{b sin\theta}{2} \frac{d(\theta)}{dt} = asin\theta \frac{d(\phi)}{dt}## ## x +\frac{b \theta sin\theta}{2} = a \phi sin\theta ## because I think... -
Electric Field inside the material of a hollow conducting sphere
Let's say I place a positive point charge inside a hollow conducting sphere. If we take a Gaussian surface through the material of the conductor, we know the field inside the material of the conductor is 0, which implies that there is a -ve charge on the inner wall to make the net enclosed...- preachingpirate24
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- Classical mechanics Conducting Conducting sphere Electric Electric field Electric flux Electrostatics Field Gauss's law Material Sphere
- Replies: 11
- Forum: Electromagnetism
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Block on a wedge connected to pulleys
if the tiny block moves downward by an amount x, the wedge should also move forward by the same amount x as they are connected by the same string whose length has to remain constant, (by differentiating it wrt time we get speed) hence I concluded that v1 = v2, but my book says otherwise what is...- Hamiltonian
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- Block Classical mechanics Pulleys Wedge
- Replies: 15
- Forum: Introductory Physics Homework Help